Emergence and genomic epidemiology of tigecycline resistant bacteria of fly origin across urban and rural China. - Related Documents




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199901.0000Emergence and genomic epidemiology of tigecycline resistant bacteria of fly origin across urban and rural China. Plasmid-mediated tigecycline resistance genes, notably the tet(X) and tmexCD-toprJ genes, have garnered considerable attention due to their transferability. This study aims to investigate the prevalence and resistance mechanisms associated with tet(X) and tmexCD-toprJ in flies, which are important reservoirs of antimicrobial resistance genes. A total of 52 tigecycline resistant bacterial isolates were collected, among which 40 (76.9 %) and 12 (23.1 %) were positive for tet(X) and tmexCD-toprJ, respectively. Tigecycline resistant bacteria were isolated from diverse geographical locations in China, with tet(X4)-positive Escherichia coli and tmexCD1-toprJ1-positive Klebsiella pneumoniae dominant among the isolates. The prevalence of tet(X) in rural area was significantly higher than that in urban area (2.7 % vs. 0.3 %; P < 0.001), while the prevalence of tmexCD1-toprJ1 shows no significant difference between urban and rural areas (0.2 % vs. 0.6 %; P > 0.05). Most tet(X)-positive strains (n = 40, 100.0 %), and 11(91.7 %) of the tmexCD1-toprJ1-positive strains exhibited multi-drug resistance. The IncFIB(Mar)/IncHI1B hybrid plasmid carrying tmexCD1-toprJ1 was identified by whole-genome sequencing analysis, which dominated the transmission of tmexCD1-toprJ1 in K. pneumoniae. Genetic context analysis showed that tmexCD1-toprJ1 was related locally to IS26, and IS26 may exacerbate the spread of tmexCD1-toprJ1 in different bacteria. In addition, the genetic structure of tmexCD1-toprJ1 also contains several antimicrobial resistance genes, including aph(3')-Ic, sul1, bla(DHA-1), bla(CTX-M-5), etc., conferring resistance to aminoglycosides, sulfonamides, and carbapenems. This study provides insights into the epidemiology and transmission dynamics of tigecycline resistance genes, informing targeted intervention strategies to mitigate antimicrobial resistance dissemination.202439476596
118510.9995Mobile Colistin Resistance and Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli from China, 1993-2019. Plasmid-mediated quinolone resistance (PMQR) genes and mobile colistin resistance (MCR) genes in Escherichia coli (E. coli) have been widely identified, which is considered a global threat to public health. In the present study, we conducted an analysis of MCR genes (mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5) and PMQR genes [qnrA, qnrB, qnrC, qnrD, qnrE1, qnrVC, qnrS, aac(6')-Ib-cr, qepA, and oqxAB] in E. coli from China, 1993-2019. From the 3,663 E. coli isolates examined, 1,613 (44.0%) tested positive for PMQR genes, either individually or in combination. Meanwhile, 262 isolates (7.0%) carried the MCR genes. Minimum inhibitory concentration (MIC) analyses of 17 antibiotics for the MCR gene-carrying strains revealed universal multidrug resistance. Resistance to polymyxin varied between 4 μg/mL and 64 μg/mL, with MIC50 and MIC90 at 8 μg/mL and 16 μg/mL, respectively. In addition, fluctuations in the detection rates of these resistant genes correlated with the introduction of antibiotic policies, host origin, temporal trends, and geographical distribution. Continuous surveillance of PMQR and MCR variants in bacteria is required to implement control and prevention strategies.202438629721
294720.9995Large-Scale Studies on Antimicrobial Resistance and Molecular Characterization of Escherichia coli from Food Animals in Developed Areas of Eastern China. Widely distributed multidrug-resistant (MDR) bacteria threaten animals and human health. Nevertheless, few antimicrobial resistance (AMR) surveys of large-scale animal-derived bacteria have been explored. Here, 1,468 (97.54%) Escherichia coli strains were isolated from 1,505 pig (1,060) and chicken (445) anal swab samples from 11 cities in Zhejiang Province, China, in 2020. These isolates had a high resistance to tetracycline (92.92%), sulfisoxazole (93.05%), florfenicol (83.11%), and ampicillin (78.27%). More than 88.68% of the strains were MDR bacteria. A low AMR ratio to the "last-resort" antimicrobials tigecycline (0.75%), colistin (1.36%), and meropenem (0.75%) were found. The AMR of E. coli from pigs was higher than that of chickens. Eighteen strains among 31 MDR strains that were resistant to "last-resort" antimicrobials could transfer the AMR genes (mcr-1, tet(X), and bla(NDM)) to the recipient strain J53, which confer colistin, tigecycline, and carbapenem resistance, respectively. The homology among mcr-1-carrying isolates was relatively high, and the sequence types were mainly ST5529, ST101, and ST354, while the homology of isolates harboring tet(X4) and bla(NDM-5) genes were different. The mcr-1, bla(NDM-5), and tet(X4) genes in strains LS45, JH51, and TZ118 were identified on the Incl2, IncHI2, and IncX1 plasmids, respectively. Moreover, tet(A), sul2, floR, and bla(TEM-1B) were the most common ARGs in 31 strains. Additionally, the heavy metals copper and zinc had a significant correlation with amoxicillin/clavulanate and tetracycline resistance. Controlling the movement of animals between cities and reducing the use of antimicrobials are effective methods to reduce the threat of AMR bacteria. IMPORTANCE Pigs and chickens are the most common food animals that are the important vectors for spreading antimicrobial-resistant pathogens among animals and humans. Limited systematic AMR monitoring of these food animal origin bacteria had been reported, especially in developed areas of China. Our study provides a comprehensive and systematic study of AMR in Escherichia coli from eastern China. The AMR of E. coli strains among the animals or cities has statistically significant differences. Moreover, the mcr-1, tet(X4), and bla(NDM-5) genes, considered resistant to the last line of AMR, were identified in part of farms. The transferability and the prevalence of these AMR strains were intensively studied. Our monitoring is comparable to human clinical research and has an essential reference for public health safety. These findings will provide early warning for AMR strains and guide the clinical use of antibiotics to control the spread of antibiotic resistance.202235950758
172630.9995Molecular epidemiology and population genomics of tet(X4), bla(NDM) or mcr-1 positive Escherichia coli from migratory birds in southeast coast of China. The emergence of multidrug-resistant (MDR) bacteria harboring tet(X4), bla(NDM) or mcr-1 posed a serious threat to public health. Wild birds, especially migratory birds, were considered as one of important transmission vectors for antibiotic resistance genes (ARGs) globally, however, few studies were performed on the genomic epidemiology of critical resistance genes among them. Isolates harboring tet(X4), mcr-1 or bla(NDM) from migratory birds were identified and characterized by PCR, antimicrobial susceptibility testing, conjugation assays, whole genome sequencing and bioinformatics analysis. A total of 14 tet(X4)-bearing E. coli, 4 bla(NDM)-bearing E. coli and 23 mcr-1-bearing E. coli isolates were recovered from 1060 fecal samples of migratory birds. All isolates were MDR bacteria and most plasmids carrying tet(X4), bla(NDM) or mcr-1 were conjugative. We first identified an E. coli of migratory bird origin carrying bla(NDM-4), which was located on a conjugative IncHI2 plasmid and embedded on a novel MDR region flanked by IS26 that could generate the circular intermediate. The emergency of E. coli isolates co-harboring mcr-1 and bla(NDM-5) in migratory birds indicated the coexistence of ARGs in migratory birds was a novel threat. This study revealed the prevalence and molecular characteristics of three important ARGs in migratory birds, provided evidence that migratory birds were potential vectors of novel resistance genes and highlighted the monitoring of ARGs in migratory birds should be strengthened to prevent the spread of ARGs in a One Health strategy.202236084501
114340.9995Antimicrobial Resistance and Virulence Profiles of mcr-1-Positive Escherichia coli Isolated from Swine Farms in Heilongjiang Province of China. ABSTRACT: The emergence and global distribution of the mcr-1 gene for colistin resistance have become a public concern because of threats to the role of colistin as the last line of defense against some bacteria. Because of the prevalence of mcr-1-positive Escherichia coli isolates in food animals, production of these animals has been regarded as one of the major sources of amplification and spread of mcr-1. In this study, 249 E. coli isolates were recovered from 300 fecal samples collected from swine farms in Heilongjiang Province, People's Republic of China. Susceptibility testing revealed that 186 (74.70%) of these isolates were colistin resistant, and 86 were positive for mcr-1. The mcr-1-positive isolates had extensive antimicrobial resistance profiles and additional resistance genes, including blaTEM, blaCTX-M, aac3-IV, tet(A), floR, sul1, sul2, sul3, and oqxAB. No mutations in genes pmrAB and mgrB were associated with colistin resistance. Phylogenetic group analysis revealed that the mcr-1-positive E. coli isolates belonged to groups A (52.33% of isolates), B1 (33.72%), B2 (5.81%), and D (8.14%). The prevalence of the virulence-associated genes iutA, iroN, fimH, vat, ompA, and traT was moderate. Seven mcr-1-positive isolates were identified as extraintestinal pathogenic. Among 20 mcr-1-positive E. coli isolates, multilocus sequence typing revealed that sequence type 10 was the most common (five isolates). The conjugation assays revealed that the majority of mcr-1 genes were transferable at frequencies of 7.05 × 10-7 to 7.57 × 10-4. The results of this study indicate the need for monitoring and minimizing the further dissemination of mcr-1 among E. coli isolates in food animals, particularly swine.202032730609
188950.9995Widespread Dissemination of Plasmid-Mediated Tigecycline Resistance Gene tet(X4) in Enterobacterales of Porcine Origin. The emergence of the plasmid-mediated high levels of the tigecycline resistance gene has drawn worldwide attention and has posed a major threat to public health. In this study, we investigated the prevalence of the tet(X4)-positive Enterobacterales isolates collected from a pig slaughterhouse and farms. A total of 101 tigecycline resistance strains were isolated from 353 samples via a medium with tigecycline, of which 33 carried tet(X4) (9.35%, 33/353) and 2 carried tet(X6) (0.57%, 2/353). These strains belong to seven different species, with Escherichia coli being the main host bacteria. Importantly, this report is the first one to demonstrate that tet(X4) was observed in Morganella morganii. Whole-genome sequencing results revealed that tet(X4)-positive bacteria can coexist with other resistance genes, such as bla(NDM-1) and cfr. Additionally, we were the first to report that tet(X4) and bla(NDM-1) coexist in a Klebsiella quasipneumoniae strain. The phylogenetic tree of 533 tet(X4)-positive E. coli strains was constructed using 509 strains from the NCBI genome assembly database and 24 strains from this study, which arose from 8 sources and belonged to 135 sequence types (STs) worldwide. We used Nanopore sequencing to interpret the selected 21 nonclonal and representative strains and observed that 19 tet(X4)-harboring plasmids were classified into 8 replicon types, and 2 tet(X6) genes were located on integrating conjugative elements. A total of 68.42% of plasmids carrying tet(X4) were transferred successfully with a conjugation frequency of 10(-2) to 10(-7). These findings highlight that diverse plasmids drive the widespread dissemination of the tigecycline resistance gene tet(X4) in Enterobacterales of porcine origin. IMPORTANCE Tigecycline is considered to be the last resort of defense against diseases caused by broad-spectrum resistant Gram-negative bacteria. In this study, we systematically analyzed the prevalence and genetic environments of the resistance gene tet(X4) in a pig slaughterhouse and farms and the evolutionary relationship of 533 tet(X4)-positive Escherichia coli strains, including 509 tet(X4)-positive E. coli strains selected from the 27,802 assembled genomes of E. coli from the NCBI between 2002 and 2022. The drug resistance of tigecycline is widely prevalent in pig farms where tetracycline is used as a veterinary drug. This prevalence suggests that pigs are a large reservoir of tet(X4) and that tet(X4) can spread horizontally through the food chain via mobile genetic elements. Furthermore, tetracycline resistance may drive tigecycline resistance through some mechanisms. Therefore, it is important to monitor tigecycline resistance, develop effective control measures, and focus on tetracycline use in the pig farms.202236125305
151260.9995Emergence of novel tigecycline resistance gene tet(X5) variant in multidrug-resistant Acinetobacter indicus of swine farming environments. Antibiotic-resistant bacteria are emerging all the time, but the continued emergence of novel resistance genes and genetic structures is even more alarming. Tigecycline is currently the important last barrier in the treatment of multidrug-resistant (MDR) infections. tet(X), a resistance gene to tigecycline, is the most prevalent and constantly emerging novel variants. In this research, we characterized two MDR Acinetobacter indicus strains to tigecycline that were identified and analyzed by antimicrobial susceptibility testing, conjugation transfer, whole genome sequencing (WGS) and bioinformatics analysis, and gene function analysis. The results showed that three tet(X) variants were carried in BDT201, including tet(X6) on the chromosome, tet(X3) on the plasmid pBDT201-2, and a novel tet(X5) variant adjacent to the ISAba1 elements on the plasmid pBDT201-3. The novel Tet(X5) variant showed 98.7% amino acid identity with Tet(X5) and was named Tet(X5.4). By expressing tet(X5.4) gene, the tigecycline minimum inhibitory concentration (MIC) values for Escherichia coli JM109 increased 32- fold (from 0.13 to 4 mg/L). BDT2076 contained tigecycline and carbapenems resistance genes, such as tet(X3), bla(OXA-58), bla(NDM-3), and bla(CARB-2). The continuous emergence of MDR bacteria and resistance genes is a global environmental health issue that can not be ignored and therefore needs to pay more urgent attention to it.202337531842
173370.9995Dissemination and Comparison of Genetic Determinants of mcr-Mediated Colistin Resistance in Enterobacteriaceae via Retailed Raw Meat Products. The global food chain may significantly promote the dissemination of bacteria resistant to antibiotics around the world. This study was aimed at determining the prevalence and genetic characteristics of Enterobacteriaceae with mcr-mediated colistin (CT) resistance in retail meat of different origins. Bacteria of the Enterobacteriaceae family carrying the mcr-1 gene were detected in 21% (18/86) of the examined samples, especially in turkey meat and liver originating from EU and non-EU countries (19%) and in rabbit meat imported from China (2%). The examined samples of the meat and liver of chicken and other poultry and of pork and beef were negative for the presence of bacteria carrying the mcr-1 to mcr-5 genes. A huge number of isolates belonging to Escherchia coli (n = 54), Klebsiella pneumoniae (n = 6), and Citrobacter braakii (n = 1) carrying the mcr-1 gene were obtained. Despite the high heterogeneity of the tested isolates, the mcr-1 gene was localized on only three types of plasmids (IncX4, IncHI2, and IncI2). The most frequent type of plasmid was IncX4, which carried the mcr-1 gene in 77% of E. coli and K. pneumoniae isolates from turkey meat and liver samples from the Czechia, Germany, Poland, and Brazil. Our findings indicate highly probable interspecies transfer of IncX4 and IncI2 plasmids within one meat sample. The co-resistance of plasmid-mediated CT resistance encoded by the mcr-1 and ESBL genes was detected in 18% of the isolates. Another noteworthy finding was the fosA3 gene coding for fosfomycin resistance in a multidrug-resistant isolate of E. coli from rabbit meat imported from China. The observed high level of Enterobacteriaceae with plasmids carrying the mcr-1 gene in retail meat reflects the need for Europe-wide monitoring of mcr-mediated CT resistance throughout the whole food chain.201931921017
161380.9995Research note: Occurrence of mcr-encoded colistin resistance in Escherichia coli from pigs and pig farm workers in Vietnam. WHO considers colistin as a highest priority critically important drug for human health, and occurrence of colistin-resistant bacteria in livestock is of health concern. The current study determined occurrence of colistin-resistant Escherichia coli in pigs and workers at pig farms in Vietnam, and investigated the genetic background for resistance. Colistin-resistant E. coli were detected from pigs in 53/116 (45.7%) farms, and from workers taking care of the pigs in 21/94 (22.3%) farms. Colistin-resistant isolates showed MIC to colistin between 4-16 mg/L, they were multidrug resistant (99%) and resistance was caused by the presence of mcr-1 genes in 97/102 (95.1%) E. coli from pigs and in 31/34 (91.1%) isolates from humans. mcr-1 is considered a plasmid-encoded gene, but this was not confirmed in the current investigation. In total, one pig isolate carried both mcr-1 and mcr-3 genes, whereas mcr-2, mcr-4 and mcr-5 genes were not detected. Shared resistance profiles between pig and human isolates on the same farm was only observed in four farms. The study showed that commensal E. coli from pigs in Vietnam constitute a reservoir for colistin-resitant E. coli, however, further studies are needed to confirm that mcr genes are associated with plasmids and their importance for human health.202037333956
114090.9995High abundance of the colistin resistance gene mcr-1 in chicken gut-bacteria in Bangladesh. Colistin is considered a last-resort reserved drug for the treatment of critical human infections by Gram-negative bacteria. Phenotypic colistin-resistance is strongly associated with plasmid-mediated mobile colistin resistance (mcr) genes. The mcr-bearing Enterobacteriaceae have been detected in many countries from environments, animals, and humans. This study investigated phenotypic colistin-resistance and the distribution of mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5 genes in chicken-gut bacteria in Bangladesh. Bacteria were isolated from poultry- and native-chicken droppings, and their susceptibilities to colistin were determined by agar dilution and E-test minimal inhibitory concentration (MIC) measurements. Multiplex polymerase chain reactions detected mcr-1 to mcr-5 genes. Overall, 61.7% (92/149) of the isolates showed colistin resistance by agar dilution assessment (MIC > 2.0 μg/mL). The phenotypic resistance was observed considerably higher in poultry-chicken isolates (64.6%, 64/99) than in native-chicken isolates (56%, 28/50; p = 0.373). All the resistant isolates showed MIC levels between > 2 and > 128 μg/mL. The mcr-genes (mcr-1and mcr-2 combined) were detected more in poultry gut bacteria (36.4%) than native-chicken isolates (20%, p = 0.06). Despite bacteria sources, mcr-genes appeared to be significantly associated with phenotypic colistin-resistance phenomena (p < 0.001). Prior colistin usage led to a substantial increase in the proportion of bacteria with mcr-genes and phenotypic resistance (p < 0.001).202033057111
1629100.9995Molecular detection of colistin resistance genes (mcr-1 to mcr-5) in human vaginal swabs. OBJECTIVE: Colistin resistance has emerged worldwide and has been threatening the efficacy of one of the last-resort antimicrobials used for treatment of multidrug resistant Gram-negative bacteria. While five colistin resistance genes (mcr-1, mcr-2, mcr-3, mcr-4 and mcr-5) have been described, few data are available on the prevalence of mcr-genes other than mcr-1 in human samples. RESULTS: In this study, the presence of five currently described colistin resistance genes (mcr 1-5) in vaginal swabs of women undergoing infertility evaluation was reported. Most samples were found to be positive for the mcr-4 (12.7%), followed by two for the mcr-2 (1.5%), two for the mcr-3 (1.5%), one for the mcr-1 (0.7%), and one for the mcr-5 (0.7%). Phylogenetic comparison demonstrated identical (mcr-1, mcr-2, mcr-3, mcr-5) or similar (mcr-4) nucleotide sequences of human samples and those of animal origins from the same city, suggesting the potential transmission of mcr genes from animals to humans. This is the first detection of mcr-2, mcr-4 and mcr-5 genes in human samples, and warrants further research to determine the spread of the mcr genes and elucidate the full epidemiology of colistin resistance genes in humans.201829463301
1206110.9995A National Antimicrobial Resistance Monitoring System Survey of Antimicrobial-Resistant Foodborne Bacteria Isolated from Retail Veal in the United States. ABSTRACT: Little is known about the prevalence of antimicrobial-resistant (AMR) bacteria in veal meat in the United States. We estimated the prevalence of bacterial contamination and AMR in various veal meats collected during the 2018 U.S. National Antimicrobial Resistance Monitoring System (NARMS) survey of retail outlets in nine states and compared the prevalence with the frequency of AMR bacteria from other cattle sources sampled for NARMS. In addition, we identified genes associated with resistance to medically important antimicrobials and gleaned other genetic details about the resistant organisms. The prevalence of Campylobacter, Salmonella, Escherichia coli, and Enterococcus in veal meats collected from grocery stores in nine states was 0% (0 of 358), 0.6% (2 of 358), 21.1% (49 of 232), and 53.5% (121 of 226), respectively, with ground veal posing the highest risk for contamination. Both Salmonella isolates were resistant to at least one antimicrobial agent as were 65.3% (32 of 49) of E. coli and 73.6% (89 of 121) of Enterococcus isolates. Individual drug and multiple drug resistance levels were significantly higher (P < 0.05) in E. coli and Enterococcus from retail veal than in dairy cattle ceca and retail ground beef samples from 2018 NARMS data. Whole genome sequencing was conducted on select E. coli and Salmonella from veal. Cephalosporin resistance (blaCMY and blaCTX-M), macrolide resistance (mph), and plasmid-mediated quinolone resistance (qnr) genes and gyrA mutations were found. We also identified heavy metal resistance genes ter, ars, mer, fieF, and gol and disinfectant resistance genes qac and emrE. An stx1a-containing E. coli was also found. Sequence types were highly varied among the nine E. coli isolates that were sequenced. Several plasmid types were identified in E. coli and Salmonella, with the majority (9 of 11) of isolates containing IncF. This study illustrates that veal meat is a carrier of AMR bacteria.202134015113
1084120.9995The emergence of colistin-resistant Escherichia coli in chicken meats in Nepal. The emergence and dissemination of colistin resistance among Gram-negative bacteria is a global problem. We initiated a surveillance of colistin-resistant and -susceptible Escherichia coli in raw meats from chicken in Nepal. A total of 180 meat samples were collected; from these, 60 E. coli strains were isolated (33.33%), of which 16 (26.66%) were colistin-resistant and harboured the mcr-1 gene. All isolates were characterised by antibiotic susceptibility testing, the presence of antibiotic resistance genes, phylogenetic analysis and plasmid replicon typing. Most of the colistin-resistant E. coli had the antibiotic resistant pattern CIP/CN/SXT/TE (43.75%). Coexistence of tet, qnr, sul and dfr genes was detected in both colistin-resistant and -susceptible E. coli. Most colistin-resistant E. coli strains belonged to phylogroup C, whereas 10% of isolates belonged to phylogroup D. Inc FIB was the dominant plasmid Inc type in the isolates. Dissemination of antibiotic-resistant E. coli in raw meats is a public health concern in Nepal and requires further investigation to ascertain the sources of contamination.201931755930
896130.9995Retrospective Screening and Analysis of mcr-1 and bla (NDM) in Gram-Negative Bacteria in China, 2010-2019. Currently, Gram-negative bacteria have developed multidrug and broad-spectrum drug resistance, and the numbers of species and strains carrying mcr or bla (NDM) genes are increasing. In this study, mcr-1 and bla (NDM) distribution of 12,858 Gram-negative bacteria isolated from wildlife, patients, livestock, poultry and environment in 14 provinces of China from 2010 to 2019 and the antibiotics resistance in regard to polymyxins (polymyxin B and colistin) and carbapenems of positive strains were investigated. A total of 70 strains of 10 species carried the mcr-1 gene, positive rates of patients, livestock and poultry, and environmental strains were 0.62% (36/5,828), 4.07% (29/712), 5.43% (5/92), respectively. Six strains of 3 species carrying the bla (NDM) gene all came from patients 0.10% (6/5,828). Two new mcr-1 gene variants (GenBank: MK965883, MK965884) were identified, one of which contains premature stop codon. The drug susceptibility results showed that all mcr-1 carriers were sensitive to carbapenems, among which, 66 strains were resistant and 4 were sensitive to polymyxins. The strains with the bla (NDM) gene had different degrees of resistance to carbapenems and were sensitive to polymyxins. The findings that species carrying mcr-1 or bla (NDM) genes were limited and mostly normal flora of opportunistic or low pathogenic organisms indicated that transfer of mcr-1 and bla (NDM) genes between bacteria was relatively limited in China. The none detection among wildlife compared with other sources supports the speculation that the emergence of and increase in polymyxins and carbapenem-resistant strains was mainly related to the selective pressure of antibiotics.202032117144
2761140.9995First reported detection of the mobile colistin resistance genes, mcr-8 and mcr-9, in the Irish environment. The emergence and dissemination of mobile colistin resistance (mcr) genes across the globe poses a significant threat to public health, as colistin remains one of the last line treatment options for multi-drug resistant infections. Environmental samples (157 water and 157 wastewater) were collected in Ireland between 2018 and 2020. Samples collected were assessed for the presence of antimicrobial resistant bacteria using Brilliance ESBL, Brilliance CRE, mSuperCARBA and McConkey agar containing a ciprofloxacin disc. All water and integrated constructed wetland influent and effluent samples were filtered and enriched in buffered peptone water prior to culture, while wastewater samples were cultured directly. Isolates collected were identified via MALDI-TOF, were tested for susceptibility to 16 antimicrobials, including colistin, and subsequently underwent whole genome sequencing. Overall, eight mcr positive Enterobacterales (one mcr-8 and seven mcr-9) were recovered from six samples (freshwater (n = 2), healthcare facility wastewater (n = 2), wastewater treatment plant influent (n = 1) and integrated constructed wetland influent (piggery farm waste) (n = 1)). While the mcr-8 positive K. pneumoniae displayed resistance to colistin, all seven mcr-9 harbouring Enterobacterales remained susceptible. All isolates demonstrated multi-drug resistance and through whole genome sequencing analysis, were found to harbour a wide variety of antimicrobial resistance genes i.e., 30 ± 4.1 (10-61), including the carbapenemases, bla(OXA-48) (n = 2) and bla(NDM-1) (n = 1), which were harboured by three of the isolates. The mcr genes were located on IncHI2, IncFIIK and IncI1-like plasmids. The findings of this study highlight potential sources and reservoirs of mcr genes in the environment and illustrate the need for further research to gain a better understanding of the role the environment plays in the persistence and dissemination of antimicrobial resistance.202336906027
1186150.9995Multidrug-Resistant Escherichia coli Strain Isolated from Swine in China Harbors mcr-3.1 on a Plasmid of the IncX1 Type That Cotransfers with mcr-1.1. An Escherichia coli strain isolated from the feces of swine at a pork slaughterhouse in Henan province China was found to possess two colistin-resistance genes, mcr-1 and mcr-3, plus 16 additional resistance genes. Genes mcr-1.1 and mcr-3.1 were identified on IncHI2 and IncX1 type plasmids, respectively. Transconjugants (containing mcr-3, mcr-1&mcr-3) were obtained that were 64- and 512-fold higher than the minimum inhibitory concentration of colistin on the recipient bacteria (E. coli C600), respectively. The IncX1 plasmid containing mcr-3.1 displayed a very specific structure compared with previous mcr-3. Variable and stable regions were similar across different plasmids, multiple insertion sequences and transposases.202032077761
969160.9995Dissemination of the rmtB gene carried on IncF and IncN plasmids among Enterobacteriaceae in a pig farm and its environment. OBJECTIVES: To investigate the prevalence and characterization of 16S rRNA methylase-producing bacteria in a pig farm and its environment in East China. METHODS: Enterobacteriaceae isolates and metagenomic DNA from 102 pig faecal samples from a pig farm and 97 soil samples taken in or around the farm were screened for the presence of 16S rRNA methylase genes. The clonal relationships of 16S rRNA methylase-positive isolates, plasmid content and other associated resistance genes were also characterized. RESULTS: Fifty-six rmtB-positive Enterobacteriaceae isolates, including 54 Escherichia coli, 1 Morganella morganii and 1 Proteus mirabilis, were recovered from 55 pig faecal samples. Nineteen rmtB-positive bacteria, including 13 E. coli, 2 M. morganii, 2 Leclercia adecarboxylata, 1 Enterobacter aerogenes and 1 Enterobacter cloacae, were recovered from 16 soil samples. Among the 75 rmtB-positive isolates, 31 and 25 also carried the qepA and bla(CTX-M) genes, respectively. The qepA gene co-localized with rmtB on the F2:A-:B1 plasmids and the bla(CTX-M-65) gene co-localized with rmtB on the F33:A-:B- plasmids. The rmtB gene was also found to be associated with the IncN plasmids. Clonal transmission of rmtB-positive E. coli isolates was observed between different pig groups and soil samples. CONCLUSIONS: Both horizontal gene transfer and clonal spread could be responsible for the dissemination of the rmtB gene in the pig farm and its environment. To our knowledge, this study is the first report of rmtB-positive bacteria from farmland soils and indicates that these antibiotic-resistant bacteria and/or resistance genes could be acquired by humans through the food chain.201121852287
2949170.9995Genomic analysis of multidrug-resistant Escherichia coli strains carrying the mcr-1 gene recovered from pigs in Lima-Peru. Antibiotic resistance is a current problem that significantly impacts overall health. The dissemination of antibiotic resistance genes (ARGs) to urban areas primarily occurs through ARG-carrying bacteria present in the gut microbiota of animals raised in intensive farming settings, such as pig production. Hence, this study aimed to isolate and analyzed 87 Escherichia coli strains from pig fecal samples obtained from intensive farms in Lima Department. The isolates were subjected to Kirby-Bauer-Disk Diffusion Test and PCR for mcr-1 gene identification. Disk-diffusion assay revealed a high level of resistance among these isolates to oxytetracycline, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, and doxycycline. PCR analysis identified the mcr-1 gene in 8% (7/87) E. coli isolates. Further, whole genome sequencing was conducted on 17 isolates, including multidrug resistance (MDR) E. coli and/or mcr-1 gene carriers. This analysis unveiled a diverse array of ARGs. Alongside the mcr-1 gene, the bla(CTX-M55) gene was particularly noteworthy as it confers resistance to third generation cephalosporins, including ceftriaxone. MDR E. coli genomes exhibited other ARGs encoding resistance to fosfomycin (fosA3), quinolones (qnrB19, qnrS1, qnrE1), tetracyclines (tetA, tetB, tetD, tetM), sulfonamides (sul1, sul2, sul3), amphenicols (cmlA1, floR), lincosamides (inuE), as well as various aminoglycoside resistance genes. Additionally, Multi Locus Sequence Typing (MLST) revealed a high diversity of E. coli strains, including ST10, a pandemic clone. This information provides evidence of the dissemination of highly significant ARGs in public health. Therefore, it is imperative to implement measures aimed at mitigating and preventing the transmission of MDR bacteria carrying ARGs to urban environments.202337473695
1732180.9995High Carriage Rate of the Multiple Resistant Plasmids Harboring Quinolone Resistance Genes in Enterobacter spp. Isolated from Healthy Individuals. Antimicrobial-resistant bacteria causing intractable and even fatal infections are a major health concern. Resistant bacteria residing in the intestinal tract of healthy individuals present a silent threat because of frequent transmission via conjugation and transposition. Plasmids harboring quinolone resistance genes are increasingly detected in clinical isolates worldwide. Here, we investigated the molecular epidemiology of plasmid-mediated quinolone resistance (PMQR) in Gram-negative bacteria from healthy service trade workers. From 157 rectal swab samples, 125 ciprofloxacin-resistant strains, including 112 Escherichia coli, 10 Klebsiella pneumoniae, two Proteus mirabilis, and one Citrobacter braakii, were isolated. Multiplex PCR screening identified 39 strains harboring the PMQR genes (including 17 qnr,19 aac(6')-Ib-cr, and 22 oqxA/oqxB). The genome and plasmid sequences of 39 and 31 strains, respectively, were obtained by short- and long-read sequencing. PMQR genes mainly resided in the IncFIB, IncFII, and IncR plasmids, and coexisted with 3-11 other resistance genes. The high PMQR gene carriage rate among Gram-negative bacteria isolated from healthy individuals suggests the high-frequency transmission of these genes via plasmids, along with other resistance genes. Thus, healthy individuals may spread antibiotic-resistant bacterial, highlighting the need for improved monitoring and control of the spread of antibiotic-resistant bacteria and genes in healthy individuals.202135052892
2022190.9995Analysis of antimicrobial resistance genes detected in multiple-drug-resistant Escherichia coli isolates from broiler chicken carcasses. Multi-drug-resistant (MDR) bacteria in food animals are a potential problem in both animal and human health. In this study, MDR commensal Escherichia coli isolates from poultry were examined. Thirty-two E. coli isolates from broiler carcass rinses were selected based on their resistance to aminoglycosides, β-lactams, chloramphenicols, tetracyclines, and sulfonamide antimicrobials. Microarray analysis for the presence of antimicrobial resistance and plasmid genes identified aminoglycoside [aac(6), aac(3), aadA, aph, strA, and strB], β-lactam (bla(AmpC), bla(TEM), bla(CMY), and bla(PSE-1)), chloramphenicol (cat, flo, and cmlA), sulfamethoxazole (sulI and sulII), tetracycline [tet(A), tet(C), tet(D), and tetR], and trimethoprim (dfrA) resistance genes. IncA/C plasmid core genes were detected in 27 isolates, while IncHI1 plasmid genes were detected in one isolate, indicating the likely presence of these plasmids. PCR assays for 18 plasmid replicon types often associated with MDR in Enterobacteriaceae also detected one or more replicon types in all 32 isolates. Class I integrons were investigated by PCR amplification of the integrase I gene, intI1, and the cassette region flanked by conserved sequences. Twenty-five isolates were positive for the intI1 gene, and class I integrons ranging in size from ~1,000 to 3,300 bp were identified in 19 of them. The presence of class I integrons, IncA/C plasmid genes, and MDR-associated plasmid replicons in the isolates indicates the importance of these genetic elements in the accumulation and potential spread of antimicrobial resistance genes in the microbial community associated with poultry.201222385320